Banana Muffins

Ingredients

• 1 1/2 cups all-purpose flour
• 1 teaspoon baking soda
• 1/2 teaspoon ground cinnamon
• 1/4 teaspoon salt
• 6 tablespoons unsalted butter (melted and slightly cooled)
• 2/3 cup light brown sugar (packed)
• 1 large egg (room temperature)
• 1 1/2 teaspoons pure vanilla extract
• 1 1/2 cups mashed ripe bananas